LED Lighting Versus Conventional

LEDs are well suited for directional light fixtures.

The incandescent light bulb invented by Thomas Edison was the only type available until the late 20th century, when compact fluorescent bulbs -- CFLs -- were introduced. Homeowners today have the additional option of light emitting diode -- LED -- bulbs. They offer advantages over the other types, but have a few disadvantages as well. When choosing light bulbs, consider factors that relate to light quality and intensity, health and economics.

LED Technology

An LED isn't a light bulb -- it's an electronic circuit component called a diode whose purpose is to convert alternating current into direct current. All diodes emit some type of light, but the semiconducting material in an LED emits visible light. The first LEDs emitted red light, but engineers found ways to manufacture versions that emit green, yellow and even blue light. White-light-emitting LEDs are rare, and most LED bulbs, which consist of clusters of individual LEDs, have phosphor coatings that glow with white light when excited by light from the LED clusters. LED bulbs sometimes contain complex solid-state circuitry.

Economic Efficiency

CFLs produce light via the excitation of gas inside the curved tube that forms the bulb, which is more efficient than producing light by heating a filament -- the process that occurs inside an incandescent bulb. By comparison, the production of light by an LED is even more efficient. To produce 800 lumens of light, an incandescent bulb consumes 60 watts, a CFl 13 to 15 watts, and an LED only 6 to 8 watts. Moreover, LEDs produce virtually no heat and last six times longer than CFLs and over 30 times longer than incandescent bulbs. The initial cost of an LED can be 5 times, or more, greater than that of a CFL, however.

Light Quality

One of the drawbacks of LED clusters is that they are directional. This makes them ideal for spotlights, but not as well suited for ambient lighting. Their directionality isn't as noticeable inside a phosphor-coated casing, because the entire casing glows, but the bulk of the light still emerges from the top of the bulb. The quality of light that an LED emits depends on the circuitry of the bulb, and there's a large difference between bulbs. The best bulbs, which include high-powered circuitry, produce full-spectrum white light comparable to that produced by halogen bulbs -- high-temperature incandescents. Lower-quality LEDs can be comparatively dim.

Health Considerations

The Occupational Safety and Health Administration has identified flickering from fluorescent bulbs as a health hazard, but because LEDs convert alternating to direct current, they never flicker. Moreover, LEDs contain no mercury -- a component of CFL bulbs -- and can be safely discarded. A third advantage of LEDs over CFLs is that the former emit no ultraviolet light, and you can place one on a desk next to you without fear of absorbing radiation. Compared to incandescent bulbs, LEDs generate virtually no heat, and an unattended LED presents little risk of starting a fire.